Impact process and apparatus for disintegrating materials



June 12, 1956 Filed March 2, 1953 L. PALLMANN 4 Sheets-Sheet .l

LUDWIG PALLMANN,

IN V EN TOR.

A T TORNEY.

IMPACT PROCESS AND APPARATUS FOR DISINTEGRATING MATERIALS Filed March 2,1953 June 12, 1956 PALLMANN 4 Sheets-Sheet 5 LUDWIG PALLMANN INVENTOR.

A7'7ORNEK June 12, 1956 PALLMANN 2,750,120

IMPACT PROCESS AND APPARATUS FOR DISINTEGRATING MATERIALS Filed March 2,1953 4 Sheets-Sheet 4 LUDWIG PALLMANN, y INVENTOR.

A TTORNEY,

United States Patent Ofiice llVIPACT PROCESS AND APPARATUS FORDISINTEGRATIN G MATERIALS Ludwig Pallmann, Zweibrucken, GermanyApplication March 2, 1953, Serial No. 339,565 22 Claims. (Cl. 241-27)This invention relates to methods and devices for mechanicallydisintegrating materials into small particles and is directed to aprocess and a power driven device for carrying out the process that areuniversally adaptable in the sense that they may be applied to theproblem of disintegrating .a Wide variety of materials, includingmaterials that defy processing by conventional grinding devices andexplosive materials that must be processed in spark-proof devices. Thisapplication is a continuation in part of my now abandoned copendingapplication Serial Number 185,212, filed September 16, 1950, andentitled Process and a Device for Grinding Materials of all Kinds.

The invention has been used successfully in continuous mass productionto reduce various Wet and dry materials to various degrees of fineness.Such diverse materials have been processed as Wood waste, lumber knots,rubber waste, textile waste, paper Waste, roots, peat, asbestos, resins,thermoplastics, bones, fruit, vegetables, meat, fish, as well as rocksand ores of various degrees of hardness and toughness. The inventionaccomplishes its purpose with such a Wide range of materials by causingthe pieces of material to be subject to rapidly successive high velocityimpacts against each other and against suitable impact surfaces. Theinvention preferably also provides progressively restricted processingzones and provides centrifugal force to cause the progressivelydiminishing pieces of material to migrate through these zones.

The preferred embodiments of the invention disclosed herein include astator impact shell and a co-operating rotary impact shell, at least oneof which is concave to form with the other a circular processing chamberor impact chamber that is preferably relatively narrow, beingsubstantially smaller in axial dimension than in diametrical dimension.The material to be processed is introduced at a central zone of thechamber preferably through a central feed opening in the stator impactshell. The two shells are slightly spaced apart and are formed withco-operating rim portions Which form a circumferential slot fordischarge of the processed material from the impact chamber.

Mounted in this processing chamber is an impact rotor or impeller andboth the rotary impact shell and the impact rotor are actuated forrotary movement relative to each other, preferably in oppositedirections. The two shells have conical inner wall portions of brokensurface configurations converging on the circumferential discharge slotand the rotor has a corresponding peripheral configuration. In thismanner the impact rotor cooperates with the converging walls to form arelatively thin peripheral processing zone of V-shaped crosssectionalconfiguration with the discharge slot of the impact chamber at the apexof the V. The broken surface of conical converging Walls providesnumerous impact surfaces in the peripheral processing zone and may be ofvarious configurations for this purpose.

Preferably the impactgrotor also co-operates with the Patented June 12,1956 impact chamber to provide a clearance space that extends radiallyin all directions from the feed opening of the chamber to thecircumferential discharge slot. Preferably the impact rotor has suitableimpact blades adjacent this clearance space and inlike manner theadjacent portions of the chamber walls may be formed with suitablevanes, ribs, bosses or the like, to provide the additional impactsurfaces. In the preferred practices of the invention, this clearancespace is progressively narrowed in cross-section to converge on thenarrow peripheral processing zone so that the progressively reducedpieces of material will be progressively confined as they migratecentrifugally to the peripheral processing zone.

While the clearance space leading to the peripheral processing zone maybe on either or both sides of the impact rotor, preferably the clearancespace is primarily between the impact rotor and the stator impact shell.The impact rotor may have central radial web that initially confines thenewly introduced material to this clearance space between the rotor andthe stator shell. A feature of the preferred practice of the inventionis the adjustability of the width of the circumferential discharge slotto control the particle size or fibre size of the finished product and afurther feature is the concept of making at least one of the two shellsadjustable axially relative to the other for the purpose of not onlyvarying the width of the circumferential discharge slot, but also ofvarying both the thickness of the peripheral processing zone and thedepth of the progressively constricted clearance space leading to theperipheral processing zone.

An outstanding feature of the invention, is its capability for reducingmaterials to fine particles or fibres with minimum heating eifect on thematerial. This capability makes possible continuous processing on alarge scale of various materials that are susceptible to damage by heatsuch as materials which must be maintained frozen and materials havingexceptional low melting points. The invention has been used successfullyto grind to powder .form a thermo-plastic material that has a meltingpoint of only 96 degrees F., and becomes more or less viscous at onlydegrees F.

Various features of the invention contribute to this capability for lowtemperature processing of materials. One important feature in thisregard is that the structure in the region of the clearance space and inthe region of the peripheral processing zone is so dimensioned andarranged, and the speeds of operation of the rotary shell and rotor areso adjusted that the pieces of material in process are in contact withthe apparatus surfaces only a small fraction of the process time, theparticles being in movement in the airstream across the process chamberfor the major portion of the processing time.

Another contributing feature is the provision for a high rate of flowcooling air through the apparatus. For this purpose the rotor and therotary shell are constructed to function as an effective centrifugalblower as well as to function as material-processing members. A furthercontributing feature is the construction of the device for high speed,high capacity operation to reduce the processing time and thereby reducethe opportunity for heat transfer from the apparatus to the material inprocess. A piece of material introduced into the process chamber may bedischarged in powder form in a time interval as short as one-half secondor shorter. In a preferred practice of the invention, a still furtherfeature in this regard is the provision of a Water cooling system tominimize the temperature of the apparatus walls.

The preferred practices of the invention are further characterized byremovable elements that may be replaced when worn excessively or may beinterchanged with different elements when desirable for processingdifferent materials. Thus fresh impact surfaces may be provided in theperipheral processing zone by replacing removable liners segments on theconvergent conical walls of the peripheral processing zone. A feature inthis regard is the concept of employing removable rings to retain theremovable liner segments, the removable rings forming the rim portionsof the two shells that define the circumferential discharge slot. Theserings may be replaced to provide new slot walls when desired.

Other features and advantages of the present invention will behereinafter apparent from the following description, particularly whentaken in connection with the accompanying drawing, in which Figure l isa view, partly in side elevation and partly in section, of oneembodiment of the invention;

Figure 2 is a front elevation of the same with the stator shell removed;

Figure 3 is a front elevation of a second embodiment of the invention;

Figure 4 is a front elevation of the second embodiment with the statorimpact shell swung open for access to the interior of the processingchamber;

Figure 5 is a longitudinal section taken as indicated by the line 5--5of Figure 3;

Figure 6 is a perspective view of the preferred form of rotor in thesecond embodiment of the invention;

Figure 7 is a fragmentary view of a rotor blade showing an auxiliaryfinger adjustably and replaceably mounted thereon;

Figure 8 is a section taken as indicated by the line 88 of Figure 7; and

Figure 9 is an enlarged perspective view of a replaceable segmentalimpact plate that may be employed in the peripheral processing zone ofthe impact chamber.

It is apparent that devices incorporating basic principles of theinvention may be constructed in various ways. Two specific embodimentsof the invention selected for disclosure herein will provide adequateguidance for those skilled in the art who may have occasion to apply theunderlying principles of the invention to various specific purposes.

In the first embodiment of the invention shown in Figures 1 and 2, theprincipal parts of the device include: a base structure generallydesignated 10 which includes a base plate 11 and an upright arm 12; acircular housing shell 13 integral with the base structure; a statorimpact shell 14 that completes the housing of the device; a rotaryimpact shell 15 that co-operates with the stator impact shell to form acircular impact chamber 16; and an impact rotor generally designated 20mounted in the impact chamber to co-operate with the walls thereof. Itis contemplated that the rotary shell 15 and the rotor 20 will beindividually actuated for rotation relative to each other. In thepreferred practices of the invention. the rotary shell and rotor willrotate in opposite directions at relatively high absolute speeds.

In the construction shown, the stator impact shell 14 is mounted on ahub 21 on the forward end of a hollow shaft 22, the shaft beingjournaled in a forward antifriction bearing 23, and in a second rearwardbearing (not shown) that is mounted in the arm 12 of the base structure.A suitable drive pulley 25 on the shaft 26 of a motor 27 is connected bya suitable belt 28 with a driven pulley 30 on the hollow shaft 22 forthe purpose of actuating the rotary impact shell 15.

The rotor 20 is shown mounted on an inner shaft 31, being retainedthereon by a suitable nut 32. The inner shaft 31 is journaled inside thehollow shaft 22 by a suitable bearing 33 inside the hub 21 and by asecond bearing (not shown) mounted inside the base structure arm 12. Adrive pulley 35 on the shaft 36 of a second motor 37 is connected by asuitable belt 38 with a driven pulley 40 on the outer end of the shaft31 for the purpose of actuating the rotor 20. As shown in Figure 2, thebase structure 10 of the described rotary assembly and the two motors 27and 37 are preferably mounted on a relatively large and heavy supportstructure 41.

The housing shell 13 preferably has a series of centrally located ports44 and the rotary shell 15 is provided with a similar series of ports 45for the intake of air into the axial region of the impact chamber 16.The housing shell 13 includes a cylindrical wall 46 which is formed witha forward rim 47 of slightly reduced diameter to define a housingopening that is normally closed by the stator impact shell 14. For thepurpose of admitting material to be processed in the impact chamber 16,the stator shell 14 has a central feed opening 50 and may be formed witha downwardly inclined feed duct 51 for deiivering material to the feedopening.

The stator impact shell 14 and the rotary impact shell 15 not onlyco-operate to form the impact chamber 16, but also are spaced apart attheir rims to form a circumferential discharge slot 52 for the dischargeof processed material. Preferably the discharge slot 52 is adjustable inwidth and a feature of the preferred practices of the invention is theconcept of mounting the stator impact shell 14 on the housing shell 13in an adjustable manner for this purpose. In the construction shown inthe drawings, the cylindrical wall 46 of the stator shell 13 is formedwith three equally spaced peripheral enlargements 53 in which arefixedly mounted corresponding screws 54. The stator impact shell 14 isprovided with three corresponding radial arms 55 which are fixedlymounted on the stator impact shell by suitable studs 56 and nuts 57 andare suitably apertured to slidingly fit onto the three fixed screws 54.Each of the three radial arms 55 is confined between a pair of nuts 58on the corresponding screw 54, which nuts may be adjusted to shift thestator impact shell bodily along its axis towards and away from thecooperating rotary impact shell 15.

At least one of the two impact shells 14 and 15 is of concaveconfiguration for the purpose of forming the impact chamber 16, both ofthe shells being concave in the present embodiment of the invention. Inthe construction shown, the two impact shells are formed with flat wallsin their central regions and are formed with conical walls in theirouter regions, which conical walls converge to the circumferentialdischarge slot 52. A feature of the preferred practices of the inventionis the concept of lining these conical wall portions with replaceableimpact plates which may be made of special wear-resisting alloys. Thus,as shown in Figure 2, a conical series of segmental impact plates 60 mayline the conical wall portion 61 of the rotary impact shell 15 and, asindicated in Figure 1, a similar conical series of segmental impactplates 62 may line the conical wall portion 63 of the stator impactshell 14. The exposed faces of the plates are irregular or of brokenconfiguration as they are formed with flutes, grooves, dovetail recessesor the like. In the construction shown, the segmental impact plates 60are retained between a shoulder 64 of the rotary impact shell 15 and aco-operating retaining ring 65, the retaining ring being releasablysecured by suitable screws 66. In like manner, the segmental impactplates 62 may be retained between a shoulder 69 of the stator impactshell 14 and a co-operating retaining ring 70 that is releasably securedby suitable screws 71.

Preferably the periphery of the impact rotor 20 is of a convergentconfiguration conforming to the crosssectional convergent configurationof the two series of segmental impact plates 60 and 62 on the conicalwall portions, respectively, of the two impact shells, so that theperiphery of the rotor 20 co-operates with the impact chamber 16 to formwhat may be termed a peripheral processing zone 72 that is of relativelysmal dimension in axial depth and is of V-shaped configuration with thecircumferential discharge slot 52 at the apex of the V. It iscontemplated that the segmental impact plates 60 and 62 lining thisperipheral processing zone will be of broken configuration to providenumerous impact surfaces around the periphery of the impact rotor 20.The surface configurations of the segmental impact plates 60 and 62 mayfor this purpose be characterized by such forms as grooves, depressions,ribs, lugs, bosses, points, sharp edges, and the like.

It is further contemplated that there wil be suitable clearance spacebetween the impact rotor 20 and the walls of the impact chamber 16 withsuch clearance space extending radially from the region of the feedopening 50 to the peripheral processing zone 72 and with the clearancespace decreasing as it approaches the peripheral processing zone.Preferably this clearance space is primarily on one side of the impactrotor 20. Thus, Figure 1 shows a clearance space 75 between the impactrotor 20 and the forward stator impact shell 14. While either or boththe rotor 20 and the stator shell 14 may be of concave configuration forthis purpose, the clearance space 16 in this instance is formed bymaking the rotor 20 of concave configuration 'with respect to thecentral wall of the stator impact shell 14. Thus the impact rotor 20,shown in Figure 1, progressively increases in thickness from its axialregion to its peripheral region.

The impact rotor-20 may be -of various constructions. In the particularform shown in Figures 1 and 2, the rotor comprises a plurality of blades78 that extend outward to the peripheral processing zone 72. Preferablythe series of blades 78 is integral with and interconnected by a centralweb or disc 80 integral therewith. It will be noted that-the web 80 liesclosely adjacent to the central flat portion of the rotary impact shell15 so that material entering the feed opening 50 of the impact chamberwill be directed against the web 80 rather than against the flat wallportion of the rotaryirnpact shell 15.

Preferably the circumferential discharge slot 52 is surrounded by asuitable annular discharge chamber 82 which is formed by the housingshell 13 with its cylindrical wall 46 in co-operation with adjacentportions of the stator impact shell 14 and the rotary impact shell 15.The finely divided processed material received by the annular dischargechamber 82 is released through a lower discharge opening 83. Thedischarge opening 33 is the entrance to a discharge passage 84 thatextends downward- 1y through the base structure and the supporting structure 41.

The operation of the device may be readily understood from the foregoingdescription. The material to be comminuted or disintegrated is fedthrough the feed duct 51 and the feed opening 50 into the impact chamber16 at a rate to occupy only a small portion of the available space inthe impact chamber so that the pieces of material in process may haveample freedom to move at high velocity through the air from one impactsurface to another. The principal impact surfaces are provided by therotor blades 78 and the two conical series of segmental impact liners 60and 62 in the peripheral processing zone 72, but other impact surfacesare provided by the central wall of the stator impact shell 14around thefeed opening 50 and by the forward face of the rotor web 80.

Each piece of the material in process is repeatedly struck andaccelerated by the impact surfaces of the rotary impact shell and therotor 20 and repeatedly strikes against the stationary impact surfacesof the stator impact shell 14. Thus with the rotary impact shell 15 andthe rotor 20 operating in opposite directions athigh relatively angularvelocity, the pieces of material in process are repeatedly acceleratedand repeatedly deflected, the pieces ricocheting from stationary impactsurfaces back into the paths of rotating impact surfaces.

The impact surface configurations may be specialized for particularmaterials to be processed in the device, especially the configurationsof the surfaces of the segmental impact plates, but with almost anybroken configuration .providingnumerous individual impact surfaces,

suitable operating speeds may be found for the rotary impact shell 15and the rotor 20 that will result in efiicierrt disintegration of anyparticular substance. The specific effect of the impacts on the materialin process will depend largely on the character of the material. Theeffect may be to tear, to abrade, to shred, to peel, to split, toshatter, etc.

Because the speeds of rotation are usually relatively high, the majorportion of the impacts tend to occur in the outer regions of the impactchamber. When the pieces in process are reduced in thickness to asufficient degree, they pass into the peripheral processing zone 72between the rotor and the segmental impact plates for high velocitymovement on exceedingly short paths with high frequency impacts betweenthe periphery of the rotor and the segmental impact plates. This finalacceleration of the disintegration process reduces the material toparticles of sufficient fineness to be thrown out centrifugally throughthe circumferential discharge slot 52 into the surrounding annulardischarge chamber 82 to drop into the discharge passage 84.

Among the factors that account for the relatively low heating effect ofthe process on the material are, first, the fact that a piece ofmaterial is processed rapidly and lingers only briefly in the impactchamber 16, second, the fact that the material is in actual contact withthe structure of the device for only a small portion of the processingperiod, third, the fact that the material in process is repeatedlyprojected into a highly effective stream of cooling air, and fourth, thefact that the relatively moving impact surfaces create small highvelocity air vortices that have substantial cooling effect and tend toentrain any particles on the metal surfaces. The device functions as aneffective centrifugal blower as well as a mechanically abrading device,air entering the axial region of the impact chamber 16 through the feedopening 50 and through the intake ports 44 and 45, the air beingdischarged centrifugally through the circumferential discharge slot 52into the annular discharge chamber 82 to pass out through the dischargepassage 84. Thus the air functions not only to cool the material inprocess, but also to entrain the material in process to carry thematerial through the peripheral processing zone 72 into and through thecentrifugal discharge slot 52. In addition, the air stream performs theuseful function of continually cleaning the various impact surfaces.

One important feature of the device of the present invention is theabsence of metallic elements which perform a grinding or crushingoperation as in conventional ball and hammer mills. This eliminates thetemperature rise inherent in conventional disintegrating equipment andalso obviates the possibility of sparking produced by metal strikingmetal. rise possible with the device of the present invention, and thefact that the pulverizing can be carried out without a grindingoperation likely to produce sparking, renders the device particularlyadapted for grinding explosive materials which have been very dangerousto process heretofore.

It can be emphasized again that the extremely low temperature rise alsomakes possible the distintegration or pulverization of organic materialthat must be maintained at a relatively low temperature to preventdeterioration of certain properties of the material being processed. Forexample, in the extraction of certain pharmaceutical compounds fromorgans of animals, the organs must be pulverized at temperatures on theorder of 60 degrees below zero, centigrade. Thus, pancreas of calvesfrozen to 60 degrees below zero, centigrade, have been pulverized in thedevice of the present invention at a temperature increase of only onedegree centigrade.

The second form of the invention shown in Figures 3 to 9, inclusive, isof the same general character as the first form and has the sameprincipal parts. As best The extremely low temperature shown in Figure5, the device includes a base structure, generally designated 90, thatis formed with an upwardly extending arm 91 and is integral with ahousing shell, generally designated 92. The housing shell 92 is formedwith a circular peripheral wall 93 and preferably is of hollowconstruction to contain a body of water 94 which is part of a suitablecirculating cooling system.

The housing of the device includes not only the housing shell 92, butalso a stator impact shell, generally designated 95, and a large ringmember 96 that surrounds the stator impact shell and abuts the circularperipheral wall 93 of the housing shell 92. In the construction shown ahollow O-ring 97 seals the juncture between the ring member 96 and thestator impact shell 95 and a second hollow O-ring 98 seals the juncturebetween the ring member and the circular peripheral wall 93.

Preferably the stator impact shell 95 is adapted for removal in aconvenient and rapid manner for access to the interior of the device,when required, and preferably the stator impact shell is also adjustableaxially relative to the housing shell 92 in the same general manner andfor the same general purpose as heretofore described. For this purpose,the stator impact shell 95 may be adjustably mounted on the ring member96 for axial adjustment relative thereto and the ring member may behingedly mounted on the housing shell 92.

In the particular construction shown in the drawings, the ring member 96carries three forwardly projecting fixed screws 100 at three equallyspaced circumferential points and the stator impact shell 95 has threecorresponding angular ears 103 (Figures 3 and each of which has anaperture 104 to slidingly embrace the corresponding screw. Each of theangular ears 103 is confined between two manually adjustable nuts 105and 106 on the corresponding screw 100 so that the stator impact shellmay be adjusted axially as desired.

As best shown in Figures 3 and 4, the ring member 96 has an integralhinge wing 107 and the housing shell 92 has a co-operating hinge wing103, which two hinge wings are pivotally interconnected by a suitablehinge pin 110 to permit the ring member, together with the stator impactshell 95, to swing from the normally closed position shown in Figure 3to the open position shown in Figure 4. For the purpose of holding thering member 96 closed in a quickly releasable manner, a suitable pair ofeye bolts 111 may be provided, each eye bolt carrying a clamping nut inthe form of a hand wheel 112. Each of the eye bolts 111 is pivotallymounted on a pin 113 between a pair of cars 114 on the housing shell 92to swing between the released position shown in Figure 4 and theclamping position shown in Figure 3. In its clamping position, each ofthe eye bolts 111 extends through a slot 115 in a corresponding car 116that is integral with the ring member 96, the manually rotatableclamping nut 112 being tightened against the outer face of the ear.

Preferably the stator impact shell 95, like the housing shell 92, iswater cooled and for this purpose is of hollow construction to contain abody of water 117. The water is maintained in circulation as part of thecooling systemby means of two flexible hoses 118.

The stator impact shell 95 co-operates with a rotary impact shell,generally designated 140, to form the usual circular impact chamber 145and also forms with the rotary impact shell the usual circumferentialdischarge slot 146. For the introduction of material into the impactchamber 145, the stator impact shell 95 has a central feed opening 147and is equipped with a feed duct or spout 148 that is attached by screws149.

The rotary impact shell 140 is mounted by screws 150 on a hub 151 thatis integral with a hollow shaft 152. A

forward bearing 155, enclosed by bearing housing 156 and cover plate157, journals the forward end of the l hollow shaft 152. The rear end ofthe shaft is journaled in a second bearing 158 that is enclosed by abearing housing 159 and covered by a plate 160. The forward bearing maybe protected by a pair of sealing rings 161 and 162, together with afelt ring 163 secured by a retaining ring 164, and the second bearing158 may be protected by sealing rings 165 and 166 at opposite ends ofthe bearing housing 159. For actuation of the rotary impact shell 140, agrooved pulley 170 keyed to the hollow shaft 152 is connected bymultiple V-belts 171 with a similar pulley 172 driven by a motor 173.

An impact rotor, generally designated 175, for the impact chamber 145 ismounted on the end of inner shaft 176 and is secured thereto by a nut177 and a safety screw 178. The inner shaft 176, which extends throughand beyond the hollow shaft 152, is journaled at its forward end by abearing 179 in the hub 151 behind a cover plate 180 and a sealingassembly 181.

This sealing assembly comprises a reinforced plastic ring 181a and asealing plate 18112 held in position by a pair of bushings, the sealingplate being mounted intermediate the bushings as clearly shown in Figure5.

The sealing assembly very effectively prevents entrance of pulverizedmaterial, which might enter behind the rotor, from working into thebearing assemblies supporting the shafts. This is particularly importantwhere the material being processed would form an explosive mixture withoil and greases present in the shaft-supporting bearings. There islittle likelihood, however, of material entering between the rotor andimpact seal. This is so, for once the material enters the device throughthe feed opening it is immediately impelled away from the rotor andescapes from the device through the discharge slot 146.

The rear end of the inner shaft 176 is also journaled in a bearing 182in the bearing housing 159 behind a cover plate 183. A second groovedpulley 187 on the rear end of the inner shaft 176 is connected bymultiple V-belts 188 with a pulley 189 driven by a second motor 190 forthe purpose of actuating the impact rotor 175.

The rotary impact shell 140 and the impact rotor 175 are driven by thecorresponding motors 173 and 190 in a manner to provide a high magnitudeof relative speed between the two and this purpose may be accomplishedby driving the rotary impact shell and impact rotor in the samedirection at different speeds. Preferably, however, the rotary impactshell and the impact rotor are driven in opposite directions, the twospeeds of rotation depending upon such factors as the diameters of therotating parts, the character of the material being processed and thedegree of fineness desired in the finished product. Usually highlysatisfactory results may be obtained by driving the impact rotor 175 ata substantially higher speed than the rotary impact shell 140.

In a device of the character described having an impact chamber 145 ofapproximately 30 inch diameter, for example, the impact rotor may bedriven at 3500 R. P. M. and the rotary impact shell may be driven at1600 R. P. M. or again the impact rotor speed may be 4100 R. P. M. andthe impact shell speed may be 3700 R. P. M. It the impact chamber issmaller, say on the order of 18 inches in diameter, the impact rotor maybe driven at 1200 R. P. M. and the rotary impact shell may be driven at400 R. P. M. These speeds may be increased when desired. Relatively highspeeds are desirable when the material in process has a low meltingpoint and must be protected against undue rise in temperature by passingrapidly through the process. Usually it is helpful also to feed thematerial at a relatively low rate when low temperatures are to bemaintained. In other words, the relative speeds of the rotor and impactshell, and the rate of feed of the material into the processing chamberwill depend to a great extent on the material being processed.

described embodiment of the invention, being formed with two innerconical Walls 191 and 192 that converge towards the circumferentialdischarge slot 146. These two conical wall portions are lined,respectively, by a conical series of segmental impact plates 193 and asecond conical series of segmental impact plates 194. As heretoforestated, such segmental bafile plates have surfaces of brokenconfigurations and may be of various forms for this purpose.

In the present embodiment of the invention, the preferred configurationfor an impact plate is shown in Figure 9 in which a segmental impactplate 193 is formed with sharp-edged ribs 195 separated by grooves 196of the same width. It will be noted in Figure 9 that the segmentalimpact plate 193 has beveled edges 197 and 198, the purpose of which isto permit anchorage of the plates by suitable retaining rings.

As best shown in Figure 5, the segmental impact plates 193 of the statorimpact shell 95 are held by a retaining ring 200 that is anchored bysuitable screws 201 in cooperation with a second retaining ring 204 thatis releasably held by screws 205. In like manner the segmental impactplates 194 of the rotary impact shell 140 are held in place by aretaining ring 207 releasably secured by screws 208 and by a secondco-operating retaining ring 209 that is releasably anchored by screws210. A feature of this construction is that the two retaining rings 204and 209 have a dual function since the two rings also serve asreplaceable rim members for the two impact shells and may be replacedwhenever it is desirable to renew the surfaces of the circumferentialdischarge slot 146.

The impact rotor 175 may be of the same general configuration as theimpact rotor in the first described embodiment of the invention. Thus,as best shown in Figures and 6, the impact rotor may comprise aplurality of radial blades 214 and a central web or disc 215 integraltherewith. Preferably two of the blades 214a, positioned diametricallyopposite each other, have root portions 216 of greater width than thecorresponding portions of the other blades, these root portions 216protruding forward towards the stator impact shell 195. As may be seenin Figure 5, the periphery of the impact rotor 175, that is to say, theend portions of the various blades 214, are of convergent configurationto form with the two series of segmental impact plates 193 and 194, athin V-shaped peripheral processing zone 217, with the circumferentialdischarge slot 146 at the apex of the V.

The circumferential discharge slot 146 is surrounded by an annulardischarge chamber 220 which communicates with a bottom discharge passage221. The discharge passage 146 may be connected with one or moredischarge ducts if desired. For example, as best shown in Figures 3 and4, a suitable hopper 222 may receive material from the discharge passage221 for delivery to a pair of discharge ducts 223.

A feature of this second embodiment of the invention is the concept ofmounting driven vanes in the discharge chamber 220 both for the purposeof continually sweeping material therefrom for centrifugal dischargeinto the passage 221, and for the purpose of serving as additionalblower means for pumping air through the apparatus. A further feature ofthe second embodiment of the invention is the concept of mounting suchvanes on the rotary imp act shell 140to be driven thereby.

As best shown in Figures 3 and 4, the rotary impact shell 140 is formedwith a circumferential radial flange 227, which serves as one side wallof the annular discharge passage 220, the other side wall being the ringmember 96. Suitable angle members 228 are mounted on the flange 227 bybolts .229 to serve as the desired vanes. In this instance, there aretwo diametrically positioned angle members 228, but more maybe added,the blower effect increasing With the number of the vanes.

A hlrther feature of this second embodiment of the invention is theprovision of further relatively large impact surfaces by the statorimpact shell for-initial processing of material introduced through thefeed opening 147. For example, as shown in Figures 4 and 5, the statorimpact shell 95 may be formed with relatively heavy radial lugs 230opposite the mid-portions of the rotor blades 214. It can be seen inFigure 5 that the radial lugs 230 co-operate with the blades 214 to forma clearance space that extends from the feed opening 147 to theperipheral processing zone 217 and that this clearance space isprogressively restricted.

This second embodiment of the invention operates in substantially thesame manner as the first embodiment of the invention and being watercooled is especially adapted for processing materials that must be keptat relatively low temperatures. The degree of fineness to which thematerial is broken down is governed primarily by the width of thecircumferential discharge slot 146 and the thickness of the peripheralprocessing zone 217. It is to be noted that when the nuts and 106 aremanipulated to change the width of the circumferential discharge slot146, the spacing between the rotor blades 214 and the forward segmentalimpact plates 193 is likewise changed, and in addition the dimension ofthe radial clearance space leading to the peripheral processing zone ischanged. Thus, if the adjustment of the nuts 105 and 106 increases thewidth of the circumferential discharge slot 146, the dimensions ofone-half of the peripheral processing zone 217 will also be increasedalong with the width of the clearance space, so that larger pieces ofthe material in process will be permitted to enter the peripheralprocessing zone and to pass through the peripheral processing zone tothe circumferential discharge slot 146.

It has been found that the effectiveness of the described apparatus forprocessing gummy substances may be greatly increased by adding asuitable finger to the impact rotor 175, for example, as indicated inFigures 7 and 8. For this purpose, one of the rotor blades 214 is shownformed with an enlargement 232 on one of its faces adjacent the tip ofthe blade, this enlargement having teeth for adjustable engagementwithcorresponding teeth on a finger member 233. A suitable screw 234releasably holds the finger member 233 on the rotor blade with the teethof the finger member engaging the teeth of the enlargement 232. Thus theinterengaged teeth not only hold the finger member rigid on the blade,but also permit radial adjustment of the finger member. The fingermember has a pointed outer end which extends into the peripheralprocessing zone 217 and may even extend partially into thecircumferential discharge slot 146, so that the finger will continuallysweep away any gummy or sticky substance that may tend to clog thecircumferential discharge slot and the peripheral processing zoneadjacent the slot.

Here again, the material being processed is maintained in an atmospherewherein there are no impacting elements which might produce a sparkwhich would serve to ignite explosive materials. Thus, the embodimentnow being described can also be used for grinding or pulverizingexplosive materials which have been heretofore very difficult anddangerous to process.

Also, it should again be seen, that the material processed is onlybriefly in contact with the impact elements of the chamber. As thematerial is entrained and carried through the chamber by the highvelocity, high turbulent air moving through the chamber, there is littlelikelihood of the material being heated as it is processed. Thus, againthe embodiment just described is particularly adapted to processmaterials which are susceptible to damage by even relatively lowtemperature rises.

The method of the present invention, whether carried out with eitherembodiment of the device herein disclosed andclaimed, or with devicesdifiering therefrom, comprises, as should now be understood, the stepsof introducing the material to be processed into a zone defined 'in partby a rapidly rotating wall element; and subjecting the material, whileconfined within the zone, to high velocity impact blows as saidparticles are moved by centrifugal forces set in motion by the rotatingwall element outwardly of the zone. The discharge movement of thematerial is augmented in the method disclosed by a high velocity, highlyturbulent air stream moving through said chamber and exiting at adischarge opening to carry the material therethrough as the particlesthereof are reduced to a size sufficiently small to pass through saiddischarge opening. The method includes the highly important step ofsubjecting the material introduced into the zone or chamber to rapidlysuccessive, high velocity impact blows to cause the same to strikerepeatedly against each other and against the impact surfaces formedinternally of the zone or chamber as the particles are entrained andcarried by the air stream through the zone or chamber. It will be seenthat in carrying out the method, the material is actually driven at ahigh velocity against the impact surfaces of the rotor and shells andricochets from one surface to the other in the disintegration process asit is moved toward the discharge opening formed by the circumferentialslot.

Although the now preferred embodiments of the present invention havebeen shown and described herein, it is to be understood that theinvention is not to be limited thereto, for it is susceptible to changesin form and detail within the scope of the appended claims.

I claim:

1. A device of the character described for dividing material into fineparticles, comprising in combination: a pair of impact shells of concavefacing configuration positioned face-to-face and coaxially mounted andforming an impact chamber of circular configuration, one of said shellshaving a central opening therein for feeding material into said chamber,said two shells having aligned rim portions forming converging wallmeans defining a circumferential discharge slot, said impact chamberhaving inner walls of broken configuration to provide numerous impactsurfaces including impact surfaces near said slot; an impact rotor insaid chamber comprising a plurality of radially extending blades havingimpact surfaces positioned adjacent said chamber impact surfaces tocause pieces of material to strike back and forth repeatedly between therotor impact surfaces and the chamber impact surfaces; the blades ofsaid impact rotor having tip portions providing clearance relative tosaid chamber restricted in the region of discharge slot to break thematerial into fine particles in said region; and power means to rotateat least one of said impact shells and said impact rotor for high speedrelative rotation therebetween.

2. A device as set forth in claim 1 in which said power means operatesthe driven impact shell and the impact rotor in opposite directions.

3. A device as set forth in claim 1 in which said rotor is of openconstruction with the side edges of said blades exposed to one of saidimpact shells to permit pieces of material in process to strike back andforth between the blades and said one shell.

4. A device as set forth in claim 3 in which the clearance between saidblades and said one impact shell is substantially greater than saidrestricted clearance in the region of said discharge slot.

5. A device as set forth in claim 4 in which said side edges of theblades are adjacent the non-rotating impact shell and the clearancebetween said rotor and said nonrotating impact shell progressivelynarrows towards the outer edges of said blades.

6. A device as set forth in claim 5 in which said rotor has a centralradial web cutting off said blades from the central portion of thedriven impact shell.

7. A device of the character described for dividing .material into fineparticles, comprising in combination: two impact shells axially alignedand forming an impact chamber of circular configuration, one of saidshells having a central opening therein for feeding material into saidchamber; means mounting the other of said shells for rotation said twoshells having rim portions forming a circumferential discharge slot, oneof said impact shells having an inner peripheral wall of brokenconfiguration adjacent said slot to provide numerous impact surfaces; arotor having a plurality of flat radially extending blades having impactsurfaces with peripheral edges adjacent said peripheral wall; meansmounting said rotor for rotation about an axis coincident with the axisof rotation of said other shell; and means to rotate said other shelland said rotor for relative movement between the two thereby to causepieces of material in the chamber to strike back and forth repeatedlybetween said plurality of impact surfaces of the rotor and said impactsurfaces of said peripheral wall.

8. A device as set forth in claim 1 in which the stator impact shell isformed with the opening and is pivotally mounted to swing open foraccess to said chamber.

9. A device as set forth in claim 1 in which said impact rotor has atleast one finger adjustably carried by a blade thereof and projectinginto said peripheral processing zone to clear away deposits of materialalong said discharge slot.

10. A device as set forth in claim 9 in which the end of said finger isof convergent configuration to conform with the configuration of saidperipheral processing zone adjacent the slot.

11. A device of the character described for dividing material into fineparticles, comprising in combination:

a stator impact shell and a co-operating rotary impact shell, at leastone of which is concave to form with the other an impact chamber that isof circular configuration in one plane and of elongated configuration ina second plane through the axis of the chamber, said stator shell havinga central opening for feeding material to the chamber, said two shellshaving rim portions spaced apart to form a circumferential slot fordischarge of the fine particles from the chamber, said two shells havingconical inner wall portions of broken surface configuration convergingon said slot; an impact rotor in said chamber formed with a plurality ofspaced blades extending outward toward said slot, the outer extremitiesof said blades being of convergent configuration to form with saidconverging inner wall portions a thin peripheral processing zone ofV-shaped cross-sectional configuration, with said discharge slot at theapex of the V; and means to rotate both said rotary impact shell andsaid impact rotor relative to each other to cause the materialintroduced through said feed opening to be reduced in size by repeatedprojections across the clearance space between the rotor and the chamberWalls and across said peripheral processing zone with high velocityimpacts by said rotor and said shells and to cause the progressivelydiminishing particles of the material to migrate centrifugally throughsaid peripheral processing zone to said discharge slot.

12. A device as set forth in claim 11 in which said discharge slot isnarrower than the cross-sectional dimension of said peripheralprocessing zone whereby the dimension of the slot determines the size ofthe processed particles.

13. A device as set forth in claim 11 in which said impact rotor, asintersected by said second plane, increases progressively incross-sectional dimension from the axis of the impact rotor to saidperipheral processing zone to 14. A device as set forth in claim 11 inwhich the conical inner wall portions of said shells are lined withremovable impact plates of broken surface configuration. 15. A device asset forth in claim 14 in which said impact plates are removably securedby removable rings and said rings form the walls of said discharge slot.

16. A device as set forth in claim 11 in which said impact rotor hasblades extending outward to said peripheral processing zone and has aradial web between said feed opening and said rotary impact shell.

17. A device as set forth in claim 16 in which a relatively small numberof said blades have portions extending beyond the rest of the bladestowards said stator impact shell.

18. A method of disintegrating material comprising the steps of:introducing the material particles into a processing zone defined inpart by a rapidly rotating wall element; reducing the size of saidmaterial particles by subjecting the material particles, while confiningthe same in said zone, to high velocity impact blows as said particlesare moved by centrifugal forces generated by said rotating Wall elementoutwardly of said zone; and discharging said particles from said zonethrough an exit circumscribing said zone as the impact blows reduce saidparticles to a size sufficient to pass through said exit.

19. A method of disintegrating material comprising the steps of:introducing the material particles into a processing zone defined inpart by a rapidly rotating wall element; reducing the size of saidmaterial particles by subjecting the material particles, While confiningthe same in said zone, to high velocity, high frequency impact blows assaid particles are carried by a high velocity, highly turbulent airstream and moved by centrifugal forces generated by said rotating wallelement outwardly of said zone; and discharging said particles carriedby said airstream from said zone through an exit circumscribing saidzone as the impact blows reduce said particles by said impacts to a sizesufiicient to pass through said exit.

20. A method of disintegrating material comprising the steps of:introducing said particles centrally into a processing chamber ofcircular configuration formed by impact shells coaxially mounted withthe rims thereof defining a circumferential discharge slot; rotatablydriving one of said shells in a direction opposite to the direction ofrotation of an impact rotor within said chamber to thereby subject saidparticles to rapidly successive high velocity impacts against eachother, said rotor, and adjacent surfaces of said shells as saidparticles are carried by centrifugal forces toward said circumferentialdischarge slot; and directing a high velocity air stream through saidchamber for discharge through said slot to carry said material particlestherethrough as said particles are reduced by said impacts to a sizesufficiently small to pass through said slot.

21. A method of disintegrating material comprising the steps of:introducing the material particles centrally into a processing chamberof circular configuration defined by a stationary wall element and acooperating rotary wall element spaced therefrom to provide acircumferentially arranged discharge slot; subjecting the materialparticles introduced into said chamber to rapidly successive, highvelocity impact blows to cause the same to strike against each other andagainst impact surfaces formed internally of said chamber as saidparticles are carried by centrifugal forces generated by said rotarywall element outwardly of said zone; and directing a high velocity airstream through said chamber for discharge through said slot to carrysaid material particles therethrough as said particles are reduced bysaid impacts to a size sufficiently small to pass through said slot.

22. A method of disintegrating material comprising the steps of:introducing said particles centrally into a processing chamber ofcircular configuration having abrading surfaces internally thereofformed by adjacent surfaces of impact shells coaxially mounted with therims thereof defining a circumferential discharge slot; rotatablydriving one of said shells in a direction opposite to the direction ofrotation of an impact rotor within said chamber to thereby subject saidparticles to rapidly successive, high velocity impact blows whereby saidparticles are driven at relatively high rates of velocity against eachother, said rotor, and the abrading surfaces of said shells as saidparticles are carried by centrifugal forces toward said circumferentialdischarge slot; and directing a high velocity air stream through saidchamber for discharge through said slot to carry said material particlestherethrough as said particles are reduced by said impacts to a sizesufliciently small to pass through said slot.

References Cited in the file of this patent UNITED STATES PATENTS247,749 Dawson Oct. 4, 1881 976,535 Woodcock Nov. 22, 1910 1,046,678Theesing Dec. 10, 1912 1,591,283 Charto-n et al. July 6, 1926 1,723,443Roth Aug. 6, 1929 2,164,409 Johnson July 4, 1939 FOREIGN PATENTS 17,424France June 13, 1913 (Addition to No. 406,503) 464,282 France 1 Jan. 9,1914 698,991 Germany Nov. 20, 1940 924,886 France Mar. 17, 1947

